Robust expression of tumor suppressor miRNA's let-7 and miR-195 detected in plasma of Saudi female breast cancer patients.

Background: Female breast cancer is frequently diagnosed at a later stage and the leading cause of cancer deaths world-wide. Levels of cell-free circulating microRNAs (miRNAs) can potentially be used as biomarkers to measure disease progression in breast cancer patients in a non-invasive way and are therefore of high clinical value.

Methods: Using quantitative RT-PCR, circulating miRNAs were measured in blood samples collected from disease-free individuals (n = 34), triple-negative breast tumours (TNBC) (n = 36) and luminal tumours (n = 57).

The molecular significance of methylated BRCA1 promoter in white blood cells of cancer-free females.

Background: BRCA1 promoter methylation has been detected in DNA from peripheral blood cells of both breast cancer patients and cancer-free females. However, the pathological significance of this epigenetic change in white blood cells (WBC) remains an open question. In this study, we hypothesized that if constitutional BRCA1 methylation reflects an elevated risk for developing breast cancer (BC), WBC that harbor methylated BRCA1 in both cancer-free females and BC patients should exhibit similar molecular changes.

Age-specific gene expression signatures for breast tumors and cross-species conserved potential cancer progression markers in young women.

Breast cancer in young women is more aggressive with a poorer prognosis and overall survival compared to older women diagnosed with the disease. Despite recent research, the underlying biology and molecular alterations that drive the aggressive nature of breast tumors associated with breast cancer in young women have yet to be elucidated. In this study, we performed transcriptomic profile and network analyses of breast tumors arising in Middle Eastern women to identify age-specific gene signatures.

Gene expression profiling in women with breast cancer in a Saudi population.

Objective: To generate consensus gene expression profiles of invasive breast tumors from a small cohort of Saudi females, and to explore the possibility that they may be broadly conserved between Caucasian and Middle Eastern populations.

Methods: This study was performed at King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia, from January 2005 to January 2007. Gene expression profiles were generated from 38 invasive breast tumors, and 8 tumor adjacent tissues TATs using BD Atlas cDNA expression arrays containing 1176 genes.

Expression of B7-H1 in breast cancer patients is strongly associated with high proliferative Ki-67-expressing tumor cells.

B7-H1, a co-inhibitory molecule, plays a role in immune escape of tumors. We have shown previously the expression of this molecule in breast cancer patients and demonstrated its association with high histological grade, progesterone and estrogen receptor negative status, all of which are known to have direct impact on cell proliferation. In the present work, we investigated the effect of proliferation, as measured by Ki-67 and mitotic count, on the induction of B7-H1.

The B7-H1 (PD-L1) T lymphocyte-inhibitory molecule is expressed in breast cancer patients with infiltrating ductal carcinoma: correlation with important high-risk prognostic factors.

B7-H1 molecule increases the apoptosis of tumor-reactive T lymphocytes and reduces their immunogenicity. Breast cancer is the second most common cause of mortality after lung cancer. Direct evidence linking B7-H1 with cancer has been shown in several malignancies; however, its expression in breast cancer has not been investigated.

Gene expression profiles of the fibroblasts from breast tumors and normal tissue compared with the tumor expression profiles.

Objective: The study was designed to examine whether the gene expression profiles of fibroblast cell lines, established from the tumor and the normal tissue from the same breast, exhibit any similarities with the profiles of the original tissues.

Methods: Fibroblast cell lines were established from invasive ductal carcinoma (IDC) and ductal carcinoma in situ (DCIS) of the breast and the adjacent normal tissues. Isolated total RNA from the cell lines and tissues were used to prepare labeled cDNA which was hybridized to Becton Dickinson Atlas microarrays for obtaining profiles of expressed genes.

Quick gene expression profiling of promyelocytic cell line HL-60.

Objective: A number of techniques have been developed to perform gene expression profiling. We report preliminary results from our exploratory study, using sequential analysis of gene expression (SAGE) technique, to profile the undifferentiated and differentiated HL-60 cells in line with our interest to characterize the cancer phenotype. The aim of the study is to evaluate the technique and to understand the molecular bases of these 2 states of cells.